docker-documentation/FAQ.md

# FAQ

Here will some Frequently Asked Questions reside

## My host is incompatible with images based on Ubuntu Jammy {#jammy}

Some x86_64 hosts running older versions of the Docker engine are not compatible with some images based on Ubuntu Jammy.

- Symptoms

    If your host is affected you may see errors in your containers such as:

    ```text
    ERROR - Unable to determine java version; make sure Java is installed and callable
    ```

    Or

    ```text
    Failed to create CoreCLR, HRESULT: 0x80070008
    ```

    Or

    ```text
    WARNING :: MAIN : webStart.py:initialize:249 : can't start new thread
    ```

- Resolution

  - Option 1 (Long-Term Fix)

    Upgrade your Docker engine install to at least version `20.10.10`. [Refer to the official Docker docs for installation/update details.](https://docs.docker.com/engine/install)

  - Option 2 (Short-Term Fix)

    For Docker CLI, run your container with:

    `--security-opt seccomp=unconfined`

    For Docker Compose, run your container with:

    ```yaml
      security_opt:
        - seccomp=unconfined
    ```

## My host is incompatible with images based on rdesktop {#rdesktop}

Some x86_64 hosts have issues running rdesktop based images even with the latest docker version due to syscalls that are unknown to docker.

- Symptoms

    If your host is affected you may see errors in your containers such as:

    ```text
    Failed to close file descriptor for child process (Operation not permitted)
    ```

- Resolution

    For Docker CLI, run your container with:

    `--security-opt seccomp=unconfined`

    For Docker Compose, run your container with:

    ```yaml
      security_opt:
        - seccomp=unconfined
    ```

## My host is incompatible with images based on Ubuntu Focal and Alpine 3.13 and later {#libseccomp}

This only affects 32 bit installs of distros based on Debian Buster.

This is due to a bug in the libseccomp2 library (dependency of Docker itself), which is fixed. However it's not pushed to all the repositories.

[A GitHub issue tracking this](https://github.com/moby/moby/issues/40734)

You have a few options as noted below. Options 1 is short-term, while option 2 is considered the best option if you don't plan to reinstall the device (option 3).

- Resolution

    If you decide to do option 1 or 2, you should just need to restart the container after confirming you have libseccomp2.4.4 installed.

    If 1 or 2 did not work, ensure your Docker install is at least version 20.10.0, [refer to the official Docker docs for installation.](https://docs.docker.com/engine/install/debian/)

  - Option 1

    Manually install an updated version of the library with dpkg.

    ```shell
    wget http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/libseccomp2_2.4.4-1~bpo10+1_armhf.deb
    sudo dpkg -i libseccomp2_2.4.4-1~bpo10+1_armhf.deb
    ```

    {% hint style="info" %}
    This url may have been updated. Find the latest by browsing [here](http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/).
    {% endhint %}

  - Option 2

    Add the backports repo for DebianBuster. As seen [here](https://github.com/linuxserver/docker-jellyfin/issues/71#issuecomment-733621693).

    ```shell
    sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 04EE7237B7D453EC 648ACFD622F3D138
    echo "deb http://deb.debian.org/debian buster-backports main" | sudo tee -a /etc/apt/sources.list.d/buster-backports.list
    sudo apt update
    sudo apt install -t buster-backports libseccomp2
    ```

  - Option 3

    Reinstall/update your OS to a version that still gets updates.

    - Any distro based on DebianStretch does not seem to have this package available
    - DebianBuster based distros can get the package trough backports, as outlined in point 2.

    {% hint style="info" %}
    RaspberryPI OS (formerly Raspbian) Can be upgraded to run with a 64bit kernel
    {% endhint %}

- Symptoms

  - 502 errors in __Jellyfin__ as seen in [linuxserver/docker-jellyfin#71](https://github.com/linuxserver/docker-jellyfin/issues/71)
  - `Error starting framework core` messages in the docker log for __Plex__. [linuxserver/docker-plex#247](https://github.com/linuxserver/docker-plex/issues/247)
  - No WebUI for __Radarr__, even though the container is running. [linuxserver/docker-radarr#118](https://github.com/linuxserver/docker-radarr/issues/118)
  - Images based on our Nginx base-image(Nextcloud, SWAG, Nginx, etc.) fails to generate a certificate, with a message similar to `error getting time:crypto/asn1/a_time.c:330`
  - `docker exec <container-name> date` returns 1970

## I want to reverse proxy a application which defaults to https with a selfsigned certificate {#strict-proxy}

### Traefik {#strict-proxy-traefik}

In this example we will configure a serverTransport rule we can apply to a service, as well as telling Traefik to use https on the backend for the service.

Create a [ServerTransport](https://doc.traefik.io/traefik/routing/services/#serverstransport_1) in your dynamic Traefik configuration, we are calling ours `ignorecert`.

```yml
    http:
      serversTransports:
        ignorecert:
          insecureSkipVerify: true
```

Then on our `foo` service we tell it to use this rule, as well as telling Traefik the backend is running on https.

```yml
    - traefik.http.services.foo.loadbalancer.serverstransport=ignorecert
    - traefik.http.services.foo.loadbalancer.server.scheme=https
```